"Cool" is a self-conscious post-modern phenomenon. To be it, you must be aware of it, yet at the same time, in a perpetual state of denial. The word itself is arbitrary, with no meaning besides a constant appropriation, and an existence without stagnation. You cannot capture it and own it, but rather, keep up with it at a jogging pace. Those who sprint, burn out...which leads to being dubbed a drop-out, a sell-out, a failure of cool. Or worse, cool itself may collapse, and move from subversiveness to mainstream. This of course, is inevitable. All counter-cultures will eventually be enveloped by popular culture, allowing their deaths to look like suicide.
This process of cultural appropriation kills the subculture and reduces it to merely a representation of the real. A Black Flag shirt found at Hot Topic, a CBGBs shirt sold at West 49--when this happens, a subculture dissipates, then is reborn again, as its members adopt new styles that appear alien to mainstream society.